Pump for hydraulic pitch changing mechanisms



March l, 1949. Y yJ.r=;. ANDERSON PUMP FOR HYDRAULIC PITGH CHANGING MECHANISMS Filed April e. 1 943 INVEN'roR LLHZ-lfsrsan ATTORNEY l Y Patented Mar. 1, i949 UNITED STATES PlrriizN'r AOFFICE PUMP FOR HYDRAULIC FITCH CHANGING MECHANISM John E.- Anderson, Portland, Conn., assigner to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Application April 8, 1943, Serial No. 482,264v

` 'z claims. (ci. 10a-161) of improved means for unfeathering the propeller' when the engine is not operating.

The individual pumps discharge into an annular manifold which, for convenience, may be supported within the supply manifold.

Other objects and advantages will be apparent from the specication and claims. vand from the accompanying drawings which illustrate what is now considered to be a preferred form of the invention.

In the drawings: Y

Fig. 1 is'largely a diagrammatic cross section of the pump in a plane perpendicular to the axis in rotation.

Fig. 2 is a reduced scale of a diagrammatic side view of the invention installed on an aircraft.

'I'he cylindrical pump actuating member I0 is rotatably mounted by means of roller bearings (not shown) on the rear end II of the propeller hub I4. The propeller I6 and hub I4 are driven from the engine (not shown) by the drive pump operating member I is stationary.

The member III is provided with an eccentric cam in the form of flange 2I. The propeller hub I4 rotates with propeller I6 and supports the six individual pump units I8 and the sump 20' from which the units draw their supply of oil.

Each piston 22 has a roller 24 bearing on the outer surface of eccentric 2|, and a ring 26 keeps the rollers in contact with the cam against the suction pull of the pistons and against centrifugal force. For assembly purposes, ring 26 may be made in sections joined as at 28. Each pump piston has two different diameters, a comparatively large diameter 30 for low pressure, and

a comparatively small diameter 32 for high pressure.

When the high pressure piston 32 moves radially inwardly sufficiently to uncover inlet pas-` sage 34 in pump body I8, oil will flow from sump 20 through passage 34 into high pressure cylinder 36, and on the out stroke the oil will be forced through passage 38 and check valve 40 into discharge manifold 42, from which it will pass through passage 44 to the control valves of the propeller.

A safety valve 46, discharging into sump 20,

maintains a comparatively high pressure in mani-` fold 42, for instance 3000 pounds per square inch.

The large diameter part 30 of each pump piston serves to scavenge the lubricating oil and all leakage that may collect within the pump trough 55, drawing the oil through inlet 48 and forcing it into sump 20 past check valve 50. This pump has capacity enough to pump air if necessary. The pressure in sump 20 may be relieved through safety valve 52 at comparatively low pressure, for instance twenty-five pounds per square inch.

Lubricating oil which is under pressure from the propeller hub returns to sump 20 through check valve 54, which may be set at about thirty five pounds per square inch.

Only one pump unit has been described but it will be understood that the other units work in similar manner all drawing oil from sump 20 and discharging through manifold 42.

Thus it will be seen that when the engine is driving the propeller the pumps I8 will rotate about the stationary eccentric 2| to provide high pressure oil through passage 44 for featherng and unfeathering the propeller.

It is also desired to provide means for unfeathering the propeller in the event the engine is inoperative. 'I'his is accomplished by means of electric motor 60 which is mounted on bracket 62 fixed to the engine nose. The motor 60 may be energized to rotate pump actuating member I0, through worm drive 64 and gears I5 and I3, and hence cause eccentric 2| to rotate relatively to the now stationary pumps I8 and provide high pressure oil for unfeathering the propeller.

Y pressure controlled means inter-connects said manifolds, for limiting the iuid pressures in said plunger-pump vunits supported by said manifold.

each of said plungers having a roller in contact `with said cam, said plungers being radially operable by rotation of said manifold around said cam, and means comprising a ring surrounding said rollers for maintaining said rollers in operative contact with said cam against the action of centrifugal force.

4. A pump comprising a stationary cam, a manifold surrounding said cam and having an inner surface forming a trough around said cam and spaced therefrom, pinp units supported by said manifold and means operatively connecting said pump'units and said cam whereby rotation of said manifold around said cam causes said units to pump oil from said trough into said manifold.

5. A pump comprising a stationary cam, an annular sump surrounding said cam and having an inner surface forming a trough around said cam and spaced therefrom, pump units supported by said sump, a discharge manifold within said sump, each pump having a two-diameter plunger vof which the larger diameters pump uid from said trough into said sump and the smaller diameters pump from said sump into said manifold,

said plungers being operable by rotation of said sump around said cam.

6. A pump adapted for attachment to the hub of a variable pitch propeller; said pump comprising a stationary cam, a sump surrounding said cam and having an inner surface forming a trough around said cam and spaced therefrom, a manifold within said sump, pump units'mounted on said sump, said units being operable by rotation of said sump around said cam for pumping from said trough into said sump. and from said sump into said manifold, in combination with pressure controlled devices interconnecting said sump, said trough, said manifold and said hub. substantially as described.

7. A pump comprising a stationary cam, means connecting said cam with a non-rotatable element to prevent rotation of said cam. a sump surrounding said cam and having an inner surfaceV forming a trough around said cam and spaced therefrom, pump units supported by said sump, a discharge manifold within said sump connected with discharge ports of said pumps. means operatively connecting said pump units and'said cam, and means for rotating said sump about said cam to cause said units to pump oil v from said trough into Vsaid sump and from said ile of this patent:

sump into saidl manifold.

JOHN E. ANDERSON.

REFERENCES CITED The following references-are of record in the UNITED STATES PATENTS Number Name Date 955,464 Lacour Apr. 9, 1910 982,632 Prather. Jan. 24, 1911 1,023,685 Rurvell Apr. 16, 1912 1,874,010 Hess Aug. 3o, 1932 2,023,785 Hoover Dec. 10, 1935 2,279,645 Sinclair Apr. 14, 1942 2,307,102 Blanchard et al Jan. 5, 1943 2,317,636 Parker Apr. 27, 1943 FOREIGN PATENTS Number Country Date 3 66 337 France 1906 

